Thermostat mechanism



I Sept. 3, 1929. P. H. HAMILTON THERMOSTAT MECHANISM Filed se t. 22, 1927 INVENTOR ATTORNEY Patented Sept. 3, 1929.

UNITED STATES 1,726,954 PATENT OFFICE.

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THEBMOBTAT MECHANISI.

Application filed September 82, 1927. Serial No. 281,881.

The present invention relates to adjustable thermostatic control means for automatic fluid heaters, and has for its object the provision of an adjustable thermostatic structure in which the adjustable elements of the thermostat may be locked against accidental or unauthorized derangement or dis placement.

It is a further object of the present invention to rovide a thermostatic structure for automatic fluid heaters in which the adjusting means is locked against displacement and at the same time protected by means of a single removable unitary cap.

Further objects will appear from the fol lowing descri tion of one form of embodiment of the evice.

Referring to the drawings- Figure 1 is a section of an automatic fluid heater provided with an embodiment of the invention;

Figure 2 is an enlar%ed detail view of the thermostat shown in ig. 1 and with the locking cover in place;

5 Figure 3 is a similar view with the lockin cover removed;

Figure 4 is an end view of the thermostat illustrated in the preceding figures and with the lockingcover m place;

Figure 5 is a sectional view of the thermo- Sta.t'

gigure 6 is a view-of the locking cover; an

Figure 7 is a section thereof.

The automatic fluid heater shown in Fig. 1 comprises a casing or receptacle 1 provided with a gas burner 2 at the base thereof, a central flue 3 being rovided to remove the products of combust1on. The gas burner 2 is sup lied with gas from a fuel supply ipe 4, t e quantity of gas supplied to the umer being regulated in accordance with the temperature of the fluid in the receptacle 1 by means of a' thermostat 5 mounted on theside of the boiler and having a portion 6 extendin into the interior of the tank 1 and expose directly to the heatof the fluid contained therein. The rece tacle 1 may of course belag'ged or insulate in the conventional manner if desired.

Referring more particularly to the thermostat, the same comprises a casin 7 having an inlet port 8 and outlet port 9, t e assage between these ports being controlle by a B5 disk valve 10 cooperating with a seat 11, as

shown in sectional Fig. 5. The valve 10 is normally urged a ainst the seat by a spring 10. The casing is provided with a boss 7 for mounting the same on the receptacle 1. The boss 7 supports the tubular pro'ection 6 wh1c h is of brass or similar metal avin a relatlvely high coeflicient of ex ansion, an has its outer end fixed in th6,%OSS 7 and carries at its inner closed end a screw threaded portion or block 12. A rod 13 of invar or SlIIlllflI' metal with a small coefficient of expansion is threaded at its inner end into the screw threaded member 12 and is provided with a sliding enlarged portion 14 at 1ts outer end, which artially projects into a recess 7" in the boss A valve operating member 15 'has one end resting against the end of the rod 13 in the, recess 7', and its other end fixed or located within the valve member 10. It will therefore be seen that an increase in temperature of the fluid with in the tank will cause the copper or brass tube 6 to expand at a reater rate than the invar rod 13 which wil cause the valve 10 to move toward the seat 11 and thereby reduce the flow of gas. A cooling of the fluid in the tank or receptacle 1 adjacent the projection 6 will have the opposlte effect, as it will cause a relative contraction between the tube 6 and the rod 13, thereby causin the gas valve 10 to open, increasing the flow of' gas.

The temperature range in which the thermostat functions is rendered adjustable by rotating the rod 13 so as to vary the amount the rod 13 extends into the threaded end 12 of the brass tube 6. This is accomplished by rotating a collar 14 mounted on the outer or free end of the rod 13 within the recess 7" which collar is pinned to the rod by means of a set screw. This collar carries an outwardly projecting member 16 which is an larly movable with respect to certain mdicia 17, this movement alterin the length of the invar rod with res ect to t e copper or brass tube 6 by virtue o the screw threaded member 12.

As the member 16 roject's beyond the surface of the casing 7 t e same is in a position to invite a tampering and unauthorized adjustment of the t ermostat. It is also in a position to receive a chance blow which would be transmitted to the somewhat delicate assembly of thermostat elements. In order to prevent guch unauthorized ad ustment and possible dama e and to lock the thermostat in an desire adjustment a cap 18 of segmental orm is provided. This cap which is of channel cross section as shown in Fig. 7 carries on its inner edge a segmental rack 19 having a plurality of teeth or depressions formed to engage with the member 16 so as to hold the same in any one of a lurality of selected positions when the cap 1s applied, the cap being held in position by means of an ear 20 constructed to receive a mostat mechanism.

It will also be evident that after the thermostat is adjusted to any selected position and the cap member 18 1s applied, the element 16 will be held in an immovable position.

It will of course be understood .that other modifications than that described may find embodiment within the scope of the appended claims.

I claim:

1. In a thermostat for fluid heaters, a recessed casing, means for adjusting said thermostat partially located within said recess a removable segmental cap normally adapted to be placed over said recess, means for holding said cap in place and a plurality of feet for s acing said cap from said casing.

2. I n a thermostat mechanism, the combination with a casin having a recess, a valve in said casing an thermo-elements for operating said valve, of a member in sald recess and connected to one of said elements and projecting outwardly therefrom for adjusting the operative re ation of said thermostat elements to said valve, and a device removably mounted on the walls of said casing and bridging said recess in the plane of movement of said member to guard the latter and provided on its inner wall with a series of elements which interlock with the outer end of said member to lock it in any position of adjustment.

3. In a thermostat mechanism, the combination with a casin having a recess, a valve in said casing and t ermo-elements for operating said valve, of a member in said recess and connected to one of said elements and projecting outwardly therefrom for adjustmg the o erative relation of said elements to said va ve, said member carrying a laterally extending arm, and a device removably mounted on the Walls of said casing and bridging said recess in the plane of movement of said member to guard the latter and provided on its inner wall with a series of elements which interlock with the outer end of. said member to lock it in any position of adjustment, said device being cut away along one edge to expose the arm on said member.

4. In a thermostat mechanism, the combination of a casing having a recess, a valve in said casing and inner and outer thermoelements, said inner element being movable axiall to operate said valve and movable rotative y to adjust its operative relation to said valve, of an operatlng member in said recess and connected to said inner element and projecting outwardly therefrom, and a device removably mounted on the walls of said casing and brid in said recess in the plane of movement 0 smdmember and provided with means arranged to engage said member and lock it against movement about the axis of said inner thermo-element while permitting movement of the latter axially. In testimony whereof, I have hereunto subscribed my name.

, PAUL H. HAMILTON; 

